Table 4.
Clinical features of six sporadic cases with SCN8A gene mutation
| Patient | Sex | Age | Age of onset | Seizure type | Motor development | Cognitive outcome | EEG (age) | MRI | Respond to AED | Hypotonia |
|---|---|---|---|---|---|---|---|---|---|---|
| Patient 1 | M | 1 y, 15 m | 2 m | Focal seizure | Head control (15 m), unable to sit alone (1 y, 15 m) | Severe ID | Asynchronous bilateral spike, spike and wave discharges, with central, parietal and frontal predominance (3 m) | None | OXC 30 mg/kg/d, VPA 32 mg/kg/d, CZP 0.6 mg/d; no seizure from 1 y | + |
| Patient 2 | M | 2 y, 8 m | 3 m | Focal seizure (3 m), myoclonic seizure (9 m) | Head control (2 y, 4 m) | Severe ID | Generalized high amplitude multi-spike and slow waves (9 m) | Normal (3 m); slight widened cerebellar sulci (8 m) | VPA 42 mg/kg/d, LTG 4.5 mg/kg/d, seizure free from 2 y | + |
| Patient 3 | M | 3 y, 6 m | 3.5 m | Focal seizure, secondary generalized seizure, status epilepticus | Can’t control head at 1-year-old | Severe ID | Diffuse slow waves in the background, spike at right central area during sleep period (1 y) | Normal (3 m) | LEV 29.4 mg/kg, OXC 49.4 mg/kg, TPM 5.9 mg/kg, VPA 23.5 mg/kg; Seizures were not controlled –during follow-up visit (before 1 y) | + |
| Patient 4 | F | 2 y, 6 m | 4 m | Focal seizure (4 m), generalized seizure (2 y, 2 m) | Head control at age of 2 y, 5 m | Severe ID | Boundary condition (4 m) | Normal (2 y) | Seizures frequency reduced by VPA 36 mg/kg/d, TPM 6.8 mg/kg/d, CZP 0.5 mg/d, and CBZ 18 mg/kg/d | + |
| Patient 5 | F | 1 y | 5 m | Focal seizure with generalization | Head control (2 m), sit independently (9 m), stand with assistance (1 y) | Normal | sharp and spike waves in the right frontal during sleep period, and 3–4 Hz slow-wave complexes in the occipital during awake period (8 m) | Normal (7 m) | Seizures were controlled by LEV (48.9 mg/kg/d), VPA (26.7 mg/kg/d), OXC 20 mg/kg/d; no seizures were reported since 8-month-old | – |
| Patient 6 | M | 1 y, 8 m | 6 m | Focal seizure | Head control (3 m), sit alone (6 m), walk (1 y, 4 m) | Normal | Normal EEG (6 m); Boundary condition (1 y, 6 m) | Normal (1 y, 6 m) | Controlled by OXC (30 mg/kg/d), no seizures reported since 18 m | – |
m months, y years, F female, M male, ID intellectual disability